Device for pneumatically loading piston assemblies into engine block cylinder bores

ABSTRACT

A device for pneumatically loading piston assemblies into engine block cylinder bores. A pneumatic piston loading tool is supported on the engine block by means of a hook hung on the lower pan rail and rests against the side of the engine block. The piston assembly is loaded into a loading sleeve and the projecting end of the piston inserted into the engine cylinder bore with the sleeve against the face of the block. The loading tool is placed in the loading position. A given force is applied to the handle of the loading tool forcing the sleeve firmly against the block. When sufficient force is applied on the handle of the loading tool a microswitch is closed and this actuates a solenoid controlled four-way pneumatic flow control valve to admit pneumatic pressure into a cylinder which actuates a plunger. As the plunger moves outwardly it drives the piston assembly with a controlled force into the cylinder bore. When the pressure or force applied to the handle is released, the flow control valve reverses and causes the plunger to be withdrawn from the cylinder bore.

ilnited States Patent Maslteli et al.

[2]] Appl. No.: 321,277

[52] US. Cl 29/252, 29/222, 29/269 [51] Int. Cl 1323p 19/04 [58] Field of Search 29/200 H, 222, 244, 269,

[56] References Cited UNITED STATES PATENTS 8/1955 Wenk et al. 29/224 6/1964 Granzer et al. 29/252 Primary Examiner-Richard J. Herbst Assistant Examiner-D. C. Crane Attorney, Agent, or Firm-Barnes, Kisselle, Raisch & Choate June 4,1974

[5 7] ABSTRACT A device for pneumatically loading piston assemblies into engine block cylinder bores. A pneumatic piston loading tool is supported on the engine block by means of a hook hung on the lower pan rail and rests against the side of the engine block. The piston assembly is loaded into a loading sleeve and the projecting end of the piston inserted into the engine cylinder bore with the sleeve against the face of the block. The loading tool is placed in the loading position. A given force is applied to the handle of the loading tool forcing the sleeve firmly against the block. When suffcient force is applied on the handle of the loading tool a microswitch is closed and this actuates a solenoid controlled four-way pneumatic flow control valve to admit pneumatic pressure into a cylinder which actuates a plunger. As the plunger moves outwardly it drives the piston assembly with a controlled force into the cylinder bore. When the pressure or force applied to the handle is released, the flow control valve reverses and causes the plunger to be withdrawn from the cylinder bore.

- 11 Claims, 7 Drawing Figures PATENTEUJUH 41974 3.813755 SHEET 3 OF 3 FIG. 5

' FIG. 6

EXHAUST PRESLSURE A m T l DEVICE FOR PNEUMATICALLY LOADING PISTON ASSEMBLIES INTO ENGINE BLOCK CYLINDER BORES This invention relates to a device for pneumatically loading piston assemblies into engine block cylinder bores. The current practice in the automotive industry is to load piston assemblies into engine blocks by hand. Hand loading of the piston assembly is undesirable for several reasons. The energy required to load the piston assembly into the cylinder is supplied by the operator. If the piston assembly being loaded is defective, that is, if it has an oversized or damaged ring or a damaged piston or ring groove or a popped out rail or ring in tight piston grooves, the operator in many instances will apply sufficient force (i.e., an abnormal force) to such defective piston assembly to load it nevertheless into the cylinder. Frequently in hand loading the oil ring will pop out of the piston ring groove prior to loading due to a false start or hesitation on the part of the operator.

It is the object of this invention to eliminate the undesirable elements in the loading of piston assemblies into engine blocks by hand. This object is achieved by substituting mechanical motion for manual motion in the loading of the piston assembly and by the use of a pneu- I matic cylinder which applies a straight line push with controlled normal loading force and speed in the loading of the piston assembly. The design of the tool is such that a defective piston assembly such as above described cannot be loaded because of the controlled normal loading force which is equal to that required for loading a normal piston assembly. If the ring is oversized or damaged or the piston or ring groove is damaged, the controlled loading force will not be sufficient to drive the piston assembly into the cylinder bore. Defective assemblies such as these will cause physical damage to'the cylinder bores if forcibly loaded in a manual operation. Such damage results in costly repairs or salvage procedures in either the engine plant or the dealership. The types of defective assemblies which load with a force equal to (Le, a normal loading force) or less than that required to load a normal assembly, such as missing or undersize rings or pistons, will not physically damage the cylinder bores and will be much less costly to remedy and, of course, will not be caught by the devices refusing to load feature. The tool is designed to insure proper alignment of the loading sleeve and piston assembly to the cylinder block and bore and give minimum piston protrusion FIG. 2 is a side elevation partly in section showing the pneumatic piston loader in operative position ready to push the piston assembly into the engine cylinder.

FIG. 3 is a fragmentary sectional view showing the piston assembly in its loaded position within the engine cylinder bore, the pneumatically operated plunger being in projected position ready for withdrawal.

FIG. 4 is a detail view showing the piston assembly ready for insertion into the loading sleeve.

FIG. 5 shows the piston assembly inserted into the loading sleeve.

FIG. 6 is a section along the line 6-6 of FIG. 2.

FIG. 7 is a schematic showing of the micro-switch and solenoid four-way flow control valve for controlling the pneumatic cylinder and plunger.

Referring to FIG. 4 there is shown a piston assembly for an internal combustion engine comprising a conventional piston l with an oil ring 2, compression rings 3, and connecting rod 4 ready for insertion into a conventional loading sleeve 5.

FIG. 1 shows a conventional engine block 6 in inverted position having cylinder bores 7 and a crankshaft 8. The pan rail of the block is designated 9. In loading piston assemblies into the cylinder bores, the engine block is inverted.

The pneumatic piston loading tool is supported by a hook 10 provided with a leg 11. A handle 12 is pivoted on the hook 10 by pin 13. The handle 12 has affixed thereto a plate in the form of a circular disk 14 provided on its face with a pad 15. Pad 15 is preferably made of resilient material such, for example, as silicon foam rubber. Disk 14 in turn has affixed thereto and supports cylinder 16. Pneumatic cylinder 16 is provided with a conventional piston 17 and piston rod 18 which carries at its outer end a plunger 19. Cylinder 16 at its opposite ends is placed in communication by two air lines or hoses l0 and 21 with a source of fluid such as air under pressure through a solenoid four-way flow control valve 22, FIG. 7. The solenoid valve is controlled by a normally open micro-switch 23 mounted on handle 12, FIG. 2. Handle 12 carries a plunger 24 biased outwardly or to the left, FIG. 6, by compression spring 25 so that the end 26 of the plunger extends outwardly or beyond nipple 27 and the micro-switch is open. The micro-switch is connected to a 110 volt A.C. source of current through a reducing transformer which reduces the voltage to around 12 volts so that the into the cylinder bore thus preventing the oil ring rail from popping out prior to loading. The loading tool also holds the loading sleeve firmly in place against the cylinder block, reducing or substantially eliminating the unabridged area the piston ring must pass through as it travels through the loading sleeve and into the cylinder.

In the drawings:

FIG. 1 is a side elevation of the pneumatic piston loader mounted on an engine block (in section) in retracted, non-loading or rest position (full lines) and in loading position (dotted lines). In this view the piston assembly has been inserted in theloading sleeve and shows the loading sleeve and piston assembly at the start of the loading operation.

solenoid is supplied through the micro-switch with l2 volt alternating current.

The sequence of motions necessary to load a piston assembly into the cylinder bore of an engine block when the engine block is in an inverted position and the loading tool is supported by the pan rail of the engine block is as follows:

The pneumatic piston loading tool is supported by hook 10 on pan rail 9 against engine block 6, FIG. 1. At this point the block would normally be on a moving conveyor line with the piston assembly moving on a conveyor line directly above the engine block.

Remove piston assembly, FIG. 4, from the conveyor, grasp the loading sleeve 5 in one hand and the piston assembly in the other hand, insert the piston assembly into the loading sleeve so that the lower edge 30 of the piston assembly protrudes through the loading sleeve, FIG. 5. The protrusion of the piston beyond the sleeve is such that the rings are held into the ring grooves by the inner wall of the loading sleeve 5, thus insuring that the oil ring rails and compression rings will not pop out of their respective grooves prior to loading the piston assembly into the cylinder.

Guide piston and loading sleeve assembly into the cylinder bore 7 of the engine block 6, FIG. 1. Push piston assembly into the cylinder bore 7 so that the end of the loading sleeve is against the surface 31 of the engine block 6, FIG. 1.

Grasp pneumatic loading tool by the handle 12, FIG. 1, and swing it 180 about pivot 13 of the hook 10, FIG. 2. This places the pad against the loading sleeve 5, FIG. 2. The plunger 19, FIG. 2, now comes in contact with the top of the piston assembly in loading sleeve 5. Actuating rod or plunger 24 contacts adjustable stop 32 mounted on hook 10, FIG. 2. When sufficient force is applied to the handle 12 of the pneumatic loading tool to overcome the tension of spring 25, FIGS. 2 and 6, as rod 24 contacts stop 32, rod 24 moves to the right, FIG. 6, and closes micro-switch 23 which energizes solenoid valve 22, FIG. 7. This results in exhausting air from line 21 and pressurizes line 20, FIG. 2.. This, in turn, forces plunger 19 against the piston ll, forcing the piston assembly into the cylinder bore 7 of the engine block 6, FIGS. 2 and 3. A device sometimes referred to as a tuning fork 33 is used to guide the end of the connecting rod of the piston assembly over the crankshaft journal 8, FIG. 3.

When the hand pressure applied to handle 12 of the pneumatic loading tool is released, rod 24 is moved to the left by spring 25 and opens micro-switch 23 which actuates solenoid valve 22, FIG. 7, causing air to exhaust through line and pressurizing line 21 returning piston 17 to a normally retracted position, FIGS. I and 7. The pneumatic loading tool is then swung to rest position on the hook I0, FIG. 1.

From the above description and referring in particular to FIG. 2, it will be seen that the loading tool insures proper alignment of the loading sleeve and piston assembly to the cylinder block and bore.

As long as pressure is applied to the handle 12, the handle acts through plate 14 and pad 15 to hold the loading sleeve firmly in place against the cylinder block. This is important because as the piston assembly moves from the initial loading position, shown in FIG. 2, to the final loaded position, FIG. 3, the joint between the loading sleeve and the cylinder bore 7 at the surface 31 is reduced to a minimum and is obviously much less than the width of the rail of the oil ring or the thickness of the compression rings. Thus the rings cannot pop outof the piston ring grooves as the piston assembly passes from the loading sleeve 5 into the cylinder bore 7. This insures that the rings will maintain their proper operative position in the piston ring grooves.

If a piston assembly meets the required specifications and is not defective, a known or normal force is required to load the piston assembly into the cylinder. However, when the piston assembly does not meet design specifications due, for example, to anoversized or damaged ring or damaged'piston or ring groove or a popped out rail or ring in a tight piston groove, the force required to load it into the cylinder is greater or abnormal. Accordingly the inside diameter of cylinder 16, the outside diameter of piston 17, and the air pressure applied against the piston 17 in the pneumatic cylinder are all correlated so that the plunger 19 applies only a normal loading force against the top of the piston and thus is ineffective to apply a greater or abnormal force to the piston such as is required in the loading of some types of defective piston assemblies into a cylinder. The force applied by the pneumatic motor and plunger 19, of course, can be controlled upwardly by increasing the pneumatic pressure and downwardly by decreasing the pneumatic pressure entering the cylinder through line 20 for a cylinder 16 and piston 17 of given dimensions or diameters. If the pneumatic pres sure in line 20 is a constant or given pressure, then the inside diameter of cylinder 16 and the outside diameter of piston 17 can be designed in size, that is, correlated with such line pressure, to apply only a normal loading force to the piston assembly being loaded into the cylinder. As thus designed the pneumatic loader will reject or refuse to load certain defective piston assemblies such as above described which require an abnormal loading force. This is a decided advantage of this pneumatic piston assembly loading tool because in the manual loading of piston assemblies into cylinder bores, loading of such defective piston assemblies is common. The operator in manual loading of piston assemblies when confronted with a defective assembly will simply apply a greater than normal loading force thereto to thereby jam the defective assembly into the cylinder.

The force required to load a normal (not defective or abnormal) piston assembly is determined empirically. Preferably by regulation of the pressure in the air supply line a force required to load a normal piston assembly is attained. The normal loading force will vary with piston size, ring tension and piston fit. For this reason a normal force of a 4" piston assembly for one engine design may not be the same as the normal force for a 4" piston assembly of a different design. By way of an example, in one engine model having a cylinder of 1 /2 inch diameter, the regulated line pressure is 50 pounds per square inch yielding a direct plunger force of approximately 88 pounds. The device is meritorious in that it will refuse to load certain defective piston assemblies, such as above described by way of example, which the operator could load by abnormal manual force. Whenever the type, design, or model of engine blocks and piston assemblies coming down the line are changed, then, of course, the air pressure and loading force are adjusted to obtain a normal loading force for such new line of engine cylinder bores and rings.

As shown in FIG. 7, the solenoid valve 22 controls air supply and exhaust to the cylinder 16. The air intake 35 is connected to a source of air under controlled pressure. Micro-switch 23 is normally open therefore the solenoid in valve 22 is de-energized and the spool is shifted left as shown. At this time compressed air passes through air intake 35 and flow control valve 38 to line 21 and into the left-hand end of cylinder 16, thus holding plunger 19 retracted. At the same time line 20 is connected through check valve 37 and solenoid valve 22 to the exhaust line 41.

When handle 12 is swung downwardly to loading position, FIG. 2 and pressure applied by the operator, rod 24 is moved to the right closing micro-switch 23 and energizing the solenoid in valve 22 shifting the spool to the right thereby connecting air intake 35 to line 20 through flow control valve 39 and connecting line 21 with exhaust line 41 through check valve 36.

This causes the plunger 19 to move to the left forcing the piston assembly into the cylinder bore from the position shown in FIG. 2 to the position shown in FIG. 3. The inward travel of the piston is, of course, arrested or stopped when the connecting rod bearing 40 contacts the crankshaft throw 8.

Release of pressure on handle 12 causes spring 25 to move rod 24 to the left opening micro-switch 23. The spring in valve 22 returns the spool to the left pressurizing line 21 through flow control valve 38 and exhausting line through check valve 37 returning plunger 19 to its rest position.

An oversize ring, damaged piston ring groove or popped out rail if manually forced into the bore will damaged the cylinder block causing an expensive warranty problem. Such defective piston assemblies the tool will not load. The defective assembly with a ring missing or an undersize ring will be loaded by this device because it can be loaded with a force equal to or less than a normal loading force but it will not cause damage to the cylinder block. This type of defect will be much less expensive to correct either in the engine plant or at the dealership.

We claim:

1. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a first support member, a second support member on the first support member movable from a rest position to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is moved from rest to operative position the pad rests against the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, valve means adapted to connect the cylinder to said source of fluid pressure, said valve means being actuated when pressure is applied to said second support member in the operative position of the second support member to thereby connect the cylinder with the source of fluid pressure which moves the plunger in a piston assembly loading direction with a normal force to force the piston assembly out of the loading sleeve into the cylinder bore.

2. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston in serted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a hooked support member adapted to be hooked over the pan rail of the cylinder block to rest against a side wall thereof. a second support member hinged to the hooked support member swingable from a rest position through an arc to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is swung from rest to operative position the pad rests against the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, valve means adapted to connect the cylinder to said source of fluid pressure, said valve means being actuated by said second support member when pressure is applied thereto in the operative position of the second support member to thereby connect the cylinder with the source of fluid pressure which moves the plunger in a piston assembly loading direction to force the piston assembly out of the loading sleeve into the cylinder bore.

3. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and with the loading sleeve located against the face of the engine block, comprising a hooked support member adapted to be hooked over the pan rail of the cylinder block to rest against a side wall thereof, a second support member hinged to the hooked support member adjacent the lower end thereof and swingable from a rest position downwardly to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is swung from rest to operative position the pad seats against the outer end of the loading sleeve to hold the loading sleeve against the face of the cylinder block surrounding the cylinder bore and the cylinder and plunger are aligned with the loading sleeve and piston assembly, a source of fluid pressure, solenoid valve means adapted to connect the cylinder to said source of fluid pressure and a switch adapted to connect the solenoid valve with a source of electricity, said switch being actuated by said second support member when pressure is applied to the second support member in the operative position of the second support member to thereby energize the solenoid valve which connects the cylinder to the source of fluid pressure which moves the plunger in a piston assembly loading direction to force the piston assembly out of the loading sleeve into the cylinder bore.

4. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a hooked support member adapted to be hooked over the pan rail of the cylinder block to rest against a side wall thereof, a second support member hinged to the hooked support member swingable to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is swung from rest to operative position the pad seats against the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, solenoid valve means adapted to connect the cylinder to said source of fluid pressure and a switch actuated by said second support member when pressure is applied thereto in the operative position of the second support member to thereby energize the solenoid valve means and connect the cylinder with the source of fluid pressure which moves the plunger in piston assembly loading direction to force the piston assembly out of the loading sleeve into the cylinder with a loading force sufficient only to load a normal piston assembly into the cylinder bore.

5. The device claimed in claim 1 wherein the area of the face of the reciprocable plunger to which fluid pressure is applied is correlated with the fluid pressure so that the loading force applied by the plunger against the piston assembly is sufficient only to load a normal piston assembly into the cylinder bore.

6. The combination set forth in claim 5 wherein the first support member has a hook at its upper end adapted to be hooked over the pan rail of the cylinder block.

7. The combination set forth in claim 6 wherein when the second support member is in operative position the cylinder and plunger are aligned with the loading sleeve and piston assembly.

8. The combination claimed in claim 3 wherein the said switch returns to off position as the second support member is relieved of pressure and the solenoid valve means is deenergized and directs fluid pressure to the plunger to return it to start position.

9. The combination claimed in claim 1 wherein the first support member includes means for removably supporting the said first member on the engine block during loading of the piston assembly.

10. The combination claimed in claim 9 wherein said means includes a hook adjacent the upper end of said first support member and adapted to be hooked over the pan rail of the engine block and a support leg adjacent the lower end of said support member adapted to rest on a side wall of the engine block.

11. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a first support member, a second support member on the first support member movable from a rest position to operative position, a cylinder supported on said second support member, means on said cylinder adapted for contact with said loading sleeve, a reciprocable plunger carried by said cylinder whereby when the second support member is moved from rest to operative position the cylinder and plunger are axially aligned with the piston, cylinder bore and loading sleeve and the means on the cylinder contacts the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, valve means adapted to connect the cylinder to said source of fluid pressure, said valve means being actuated when pressure is applied to said second support member in the operative position of the second support member to thereby connect the cylinder with the source of fluid pressure which moves the plunger in a piston assembly loading direction with a normal force to force the piston assembly out of the loading sleeve into the cylinder bore.

P0405) UNITED STATES PATENT UFFECE (5/69) CERTIFICATE OF CORRECTION Patent No. 3,813,755 Dated June 4, 1974 Inventor-(s) John S. Maskell and Roger D. Dykehouse It is certified that error appears in the above-identified patent and that said Letters Patsnt are hereby corrected as shown below:

Column 2, line 37 "10" should be ----20-- Column 5, line 11 "damaged" should be -damage- Signed and sealed this 15th day of October 197 :s

(SEAL) Attest:

' MCCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a first support member, a second support member on the first support member movable from a rest position to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is moved from rest to operative position the pad rests against the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, valve means adapted to connect the cylinder to said source of fluid pressure, said valve means being actuated when pressure is applied to said second support member in the operative position of the second support member to thereby connect the cylinder with the source of fluid pressure which moves the plunger in a piston assembly loading direction with a normal force to force the piston assembly out of the loading sleeve into the cylinder bore.
 2. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a hooked support member adapted to be hooked over the pan rail of the cylinder block to rest against a side wall thereof, a second support member hinged to the hooked support member swingable from a rest position through an arc to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is swung from rest to operative position the pad rests against the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, valve means adapted to connect the cylinder to said source of fluid pressure, said valve means being actuated by said second support member when pressure is applied thereto in the operative position of the second support member to thereby connect the cylinder with the source of fluid pressure which moves the plunger in a piston assembly loading direction to force the piston assembly out of the loading sleeve into the cylinder bore.
 3. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and with the loading sleeve located against the face of the engine block, comprising a hooked support member adapted to be hooked over the pan rail of the cylinder block to rest against a side wall thereof, a second support member hinged to the hooked suppoRt member adjacent the lower end thereof and swingable from a rest position downwardly to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is swung from rest to operative position the pad seats against the outer end of the loading sleeve to hold the loading sleeve against the face of the cylinder block surrounding the cylinder bore and the cylinder and plunger are aligned with the loading sleeve and piston assembly, a source of fluid pressure, solenoid valve means adapted to connect the cylinder to said source of fluid pressure and a switch adapted to connect the solenoid valve with a source of electricity, said switch being actuated by said second support member when pressure is applied to the second support member in the operative position of the second support member to thereby energize the solenoid valve which connects the cylinder to the source of fluid pressure which moves the plunger in a piston assembly loading direction to force the piston assembly out of the loading sleeve into the cylinder bore.
 4. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a hooked support member adapted to be hooked over the pan rail of the cylinder block to rest against a side wall thereof, a second support member hinged to the hooked support member swingable to operative position, a cylinder and a pad supported on said second support member, a reciprocable plunger carried by said cylinder whereby when the second support member is swung from rest to operative position the pad seats against the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, solenoid valve means adapted to connect the cylinder to said source of fluid pressure and a switch actuated by said second support member when pressure is applied thereto in the operative position of the second support member to thereby energize the solenoid valve means and connect the cylinder with the source of fluid pressure which moves the plunger in piston assembly loading direction to force the piston assembly out of the loading sleeve into the cylinder with a loading force sufficient only to load a normal piston assembly into the cylinder bore.
 5. The device claimed in claim 1 wherein the area of the face of the reciprocable plunger to which fluid pressure is applied is correlated with the fluid pressure so that the loading force applied by the plunger against the piston assembly is sufficient only to load a normal piston assembly into the cylinder bore.
 6. The combination set forth in claim 5 wherein the first support member has a hook at its upper end adapted to be hooked over the pan rail of the cylinder block.
 7. The combination set forth in claim 6 wherein when the second support member is in operative position the cylinder and plunger are aligned with the loading sleeve and piston assembly.
 8. The combination claimed in claim 3 wherein the said switch returns to off position as the second support member is relieved of pressure and the solenoid valve means is deenergized and directs fluid pressure to the plunger to return it to start position.
 9. The combination claimed in claim 1 wherein the first support member includes means for removably supporting the said first member on the engine block during loading of the piston assembly.
 10. The combination claimed in claim 9 wherein said means includes a hook adjacent the upper end of said first support member and adapted to be hooked over the pan rail of the engine block And a support leg adjacent the lower end of said support member adapted to rest on a side wall of the engine block.
 11. A device for loading a piston assembly into the cylinder bore of an engine block after the piston assembly has been inserted into a loading sleeve so that the lower end of the piston projects beyond the end of the loading sleeve with the loading sleeve encompassing the piston ring set and with the projecting end of the piston inserted into the engine cylinder and the loading sleeve located against the face of the engine block, comprising a first support member, a second support member on the first support member movable from a rest position to operative position, a cylinder supported on said second support member, means on said cylinder adapted for contact with said loading sleeve, a reciprocable plunger carried by said cylinder whereby when the second support member is moved from rest to operative position the cylinder and plunger are axially aligned with the piston, cylinder bore and loading sleeve and the means on the cylinder contacts the outer end of the loading sleeve to hold the sleeve against the face of the cylinder block surrounding the cylinder bore, a source of fluid pressure, valve means adapted to connect the cylinder to said source of fluid pressure, said valve means being actuated when pressure is applied to said second support member in the operative position of the second support member to thereby connect the cylinder with the source of fluid pressure which moves the plunger in a piston assembly loading direction with a normal force to force the piston assembly out of the loading sleeve into the cylinder bore. 